Sound receiving apparatus



May 2, 1933.

I. c. CLEMENT SOUND RECEIVING APPARATUS Filed Oct. 31, 1929 m y I A TT'ORNEY Patented May 2, 1933 UNITED STATES PATENT OFFICE IVAN C. CLEMENTQOF GREENWOOP, MASSACHUSETTS, ASSIGNOR TO SUBMARINE- SIG- NAL COMPANY, 013 BOSTON, MASSACHUSETTS, A CORPORATION OF BOUN RECEIVING APPARATUS Application filed October 31 1929. Serial No. 403,825.

The present invention relates to subaqueous sound receiving devices, and more particularly to such devices which are mounted in the skin of a vessel.

To provide a good so called skin mounted instrument there are usually two factors, among others, which demand careful con sideration. The device must be rugged; it

must be possible to install it in a vessel and be certain that it will stand up under severe weather conditions without breaking down or leaking and produce good results for a long period of time without excessive tests, examinations or repairs. The device must also be free from acoustic vibrations.

In the present invention, both of these aims are accomplished to a remarkable degree, due to the particular construction employed.

In the prior art, it has been common practice to use rubber insulation for acoustic damping, but such insulation has not always been used in the manner to accomplish the best possible acoustic damping. This is probably due to the fact that the sound device was clamped in such a manner that stresses were set up by bending which caused extraneous vibrations. Such extra .neous vibrations may be set up where "the clamping is accomplished through fastening at two points to the ships skin. If the vibration of the structures at these two points is not in the same phase and does not p'os sess substantially the same amplitude, there are liable to be some extraneous vibrations present.- In making the present invention,

I discovered this difliculty and have made a construction in which this efiect is entirely remedied, at the same time acoustically insulating the entire sound receiving a unit as a whole.

This construction also provides excellent means for maintaining a watertight installation which remains watertight. I

In the present construction, I also provide a special type of diaphragm, particularly adapted for skin mounted construction because of its mechanical and acoustic properties. I 4

Further objects and aims of the present invention, as well as advantages over the prior art, will be more fully understood from a consideration of the following description of the embodiment of the same in connectionwith the drawing showing a sectional view of the device.

In the drawing, the ships skin is'represented as-1. A'hole is cut in the skin in which is mounted the heavy ring 2 having as an integral portion a cylindrical neck 24 fitting within the edge of the hole. The ring 2 is riveted to the ships skin or plate by the rivets 5 and is made tight by a gasket 20 or 'calking between the plating and the ring. To further secure tlrering 2, it is welded at 4 to the ships skm. The ring 2 is formed with, an inwardly extending flange 25, the purpose of which will be discussed'more fully later.

The hydrophone unit 9 is inserted from the outside of the vessel and must, therefore, be installed when the ship is in dry 'dock. It is'formed of a cylindrical shell 26 with an outwardly extending .flange portion 21, the outer face 10 of which forms' a continuous surface with the ships skin and flange 25 is the insulatingelement .13, while between the cylindrical wall 26 and the flange 25 is the insulating element- 14. Theseacoustic insulating elements are pref erably one piece and are put over the shell of the hydrophone unit from the back end. In this manner they are securely and firmly held in position.

The shell 2ti is threaded on the outer side at 27 to receive a threaded collar 8 which clamps the unit securely to the inwardly extending flange 25. Between the collar 8 and the flange 25 is the insulating ring 6 and the clamping ring .7. It will be noted that the hydrophone unit is clamped to the heavy ring 2 bystr'aight pressure clamping and compression of the flange of the ring itself without forces such as bending or torsion being present. The clamping is effected be-' tween parallel surfaces substantially in an j Jphragm formed. hatthis insert takes -fahgnment perpendicular gto tfhe diaphragm: outer gfillg'galndiparfly intfljhe diaphrggm I I Surface/L, H, portion oneitherside oitheclamping-sat;g; g Y 'TheIin-diofthe hydrophoneiunit is elolsefdjqface. j I I I ,i'ffyfl' by.suitable'watentight mechanism ithroughflj' ln testimony: whereof I'aflixm g i tm- 5 whichthzecable 28is conductedtothemi cro y "7*1VANCJGL MEIQETQQi/flfy-g ff p p The diaphragm '11 of the hydrophone is r e o g maIde-of soft rubber and sits; inaseatformed j I b y'theinwardlyextending fiangef fltl andij-z zm l :j;=, I theshoulder30. ;Ontheoutsideitis'flush 7 with'the skin oftheshipandisheldinthis- 'K'' Y J ff 1 7 7 position by being cemented to'the metal andZy;ga /1, 3

' i I"'E;"I"'ibyi the clampingfpieees.1 6 am The, U clampin element" 16rests against thenare 'r'ow nec' ofthediaphragmnndpressure isjg' z p 7 o p I [1 i w BXQItGdlIPOILlbibQYIfihG ringfil threading in the in n'er' side of the shell :26.IThe dia.-fg fl i j v I I j I phrag'm' 11 is fermed with'aheavy' outer I j 'g'jf" wedge thinnerdneckQSandathickeenter I; My 7 fioportionyjlt maybe-moldedaandwhas set-, gg 'thereinzaringdnsert15, preferablymade of v I v v I f"somehard fibrousmaterialgvTheelementlfi I j I I and theconstructionoftheseat for-the"dia-, jflf' ,1 I v 1 upp'r actically theentire' neckarea andthere. j j f fore prevents" any'cold'fiowof''rnbber'beg; Y I 1 tween theclamping-surfaces. Inthisman- I v v I v her, the j'oint'ismaintainedWatertightand; [1; I

- has no tendency'to leak after a time."ln fffg o f]: p p ;-z3 fl'addition,-;theminsert;strengthens. the, dia-- I I 95 phragm' and-preventscert*inydetrimental; ;f[ frictional losses. g i y 'The microphone buttonli is mounted on v astem l8-whichisimolded with-a'plate;in w asthediaphmgm. A v a -,--,:,1oc

The whole structure is one'ada table for a skin mounted installation and gecause-of the construction almost entirely eliminates transmission of ships sounds from the hull 40 or skin to the so'undreceiver. v

7 This is in part accomplished,it is believed; because of the suspension of the unit' entirely on the heavy inertia ring andbecauseof the manner of clamping the unitto. the ring. Having no described my invention, I

claim: I 1. In a sound receivin device a casinghaving an inwardly" extn ing flange on one side forming a seat, a rubber diaphragm set- 5 ting on said seat, saiddiaphragm having a narrow neck portion, a'ring of fibrous material moulded in the neck portion of said diaphragm and extending a short distance into the diaphragm 'proper and means for clamping the diaphragm in" its neck portion to said seat. c

22 In a sound receivin device, a diaphragm of soft rubber having an outer ring portion, a narrower neck portion adjacent thereto and a diaphragm proper. portion having its surface projectedforward of the neck portion to make said portion substantially thicker than the neck portion and a rin of fibrous material posltioned in the o5 nec portion and extending partly into the 

